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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 102 |
| 3 | 2862 |
| 4 | 34960 |
| 5 | 252375 |
| 6 | 1284066 |
| 7 | 5105212 |
| 8 | 16912512 |
| 9 | 48700845 |
| 10 | 125512750 |
| 11 | 295649706 |
| 12 | 646497072 |
| 13 | 1328022787 |
| 14 | 2586463530 |
| 15 | 4811211000 |
| 16 | 8598455296 |
| 17 | 14835732057 |
| 18 | 24812155062 |
| 19 | 40359796390 |
| 20 | 64032402000 |
[0,1,102,2862,34960,252375,1284066,5105212, 16912512,48700845,125512750,295649706,646497072, 1328022787,2586463530,4811211000,8598455296, 14835732057,24812155062,40359796390,64032402000] |